The present invention relates to a motor.
Japanese Laid-Open Patent Application No. 2012-115085 describes an example of a rotor having a permanent magnet field Lundell configuration. In the prior art, the rotor is used in a motor. The rotor includes two rotor cores, which are stacked upon each other, and a field magnet, which is disk-shape and located between the rotor cores. Each of the rotor cores includes a plurality of claw poles arranged in a circumferential direction. The field magnet causes the claw poles of the rotor cores to function as poles that alternately change in the circumferential direction.
In addition to the field magnet, the rotor described in Japanese Laid-Open Patent Publication No. 2012-115085 includes back surface magnets and interpolar magnets that serve as commutator magnets. Each of the back surface magnets is located on a back surface of a claw pole, that is, between the claw pole and the field magnet. Each of the interpolar magnets is located between claw poles that are adjacent to each other in the circumferential direction. The commutator magnets reduce leakage flux of the rotor.
In a rotor that includes commutator magnets, there is no description of how the commutator magnets are fixed in the rotor, and there is a need for fixing the commutator magnets in a desirable manner.
Furthermore, an interior permanent magnet (IPM) rotor that has magnets embedded in a rotor core is known in the art (refer to, for example, Japanese Laid-Open Patent Publication No. 2002-252947). The rotor disclosed in Japanese Laid-Open Patent Publication No. 2002-252947 includes a rotor core including a plurality of insertion holes arranged in the circumferential direction. Magnets are inserted in the insertion holes so that magnets with magnetic poles functioning as the N poles on the outer side in the radial direction and magnets with magnetic poles functioning as S poles on the outer side in the radial direction are alternately arranged in the circumferential direction.
The rotor disclosed in Japanese Laid-Open Patent Publication No. 2002-252947 includes a plurality of magnets. This increases the number of components. Thus, there is room for improvement in terms of assembling efficiency.
In the motor disclosed in Japanese Laid-Open Patent Publication No. 2012-115085, magnetic saturation may occur in the claw poles of the rotor core. In the magnetic flux generated by the field magnet, the magnetic saturation lowers the ratio of the magnetic flux that is effective for the rotation of the rotor. Thus, the desired output cannot be obtained.